Various systems are dependent on applying energetic electrons in systems characterized by the absence of vacuum conditions. One such system uses electrons to reduce or eliminate volatile organic compounds contained in gas flows. This application is described, for example, in U.S. Pat. Nos. 5,319,211, 5,357,291 and 5,378,898. Electrons have also been used to reduce noxious odors and to destroy or reduce other compounds including inorganic materials and other toxics. See for example U.S. Pat. No. 4,396,580, U.S. Pat. No. 4,752,450 and U.S. Pat. No. 5,108,565. Toxics in this application means poisonous or disease causing toxins in air, other gasses, mists or attached to fine particles. Toxics are intended to include within its scope, hazardous and/or odoriferous compounds and other pollutants found or introduced into air or other gasses. In general a primary purpose of these systems has been that of reducing toxic, noxious and/or hazardous materials appearing in various forms in the environment. Also electrons have been used in sterilization processes, both for medicinal products and for food, curing of inks, plastics, paints and other compounds that require heat or radiation to stabilize them in their final useful form.
Electron beams have been created for these purposes using a vacuum unit including a source for electrons that are directed to an end window of the unit. The window is sealed with a thin foil (the window foil to maintain the vacuum and to separate the vacuum from the surrounding area at atmospheric or other conditions). The foil must be thin enough to permit electrons to pass through with a minimum loss of energy but strong enough to resist atmospheric pressure on the vacuum. In general, the foil is mounted against a metallic plate with openings throughout to provide structural support to the thin foil. An accelerating voltage is applied between the source and the plate to attract the electrons to the window area with sufficient energy to pass through the foil. However, electron beam (e-beam) devices in use suffer from short mean time between failures, limited power output, or high costs for large power output. Failure modes arise from failures of the source of emissions and failures of the foil due to pinholes caused by poor metallurgical integrity or through excessive heating by electrons passing through or a combination of both.